Roller pump



provided with a suitable mounting bracket.

United States Patent ROLLER PUMP James J. Becher, Chicago, 111., assignor, by direct and mesne assignments, to Roll-Flex Industries, Inc., a corporation of Illinois Application April 27, 1955, Serial No. 504,197

4 Claims. (Cl. 103-149) This invention relates to a sanitary and leakproof pump and more particularly is concerned with a pump of the type in which elements of fluid are progressively forced through a system of collapsible tubing without coming into contact with the active parts of the pump.

This type of pump is generally characterized by a cylindrical casing in which a central rotatable shaft is journalled in driving relationship With planetary rollers that progressively compress a loop of collapsible tubing against the cylindrical outer wall of the casing to force a fluid forwardly of the roller and set up a suction effect rearwardly thereof.

It is the principal object of the present invention to provide a pump that offers a uniform load to a driving motor or other means; that is economical to produce and maintain; that is efficient in operation; and that is of a durable construction requiring but a minimum of movable parts.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a perspective view of a roller pump with the outer casing member removed;

Fig. 2 is a side view, partially in section, of an assembled pump; and

Fig. 3 is a view taken in the vertical plane of line 3-3 of Fig. 2.

The pump comprises a two part casing that defines a cylindrical pumping chamber 11. The main casing member 12 is of hollow cylindrical shape, one end being open and the other being formed with an integral side wall 13. The side wall 13 carries an open ended integral tubular cylindrical extension 14 that communicates with the pumping chamber 11 through a similar sized opening 15 in the side wall. The smooth inner cylindrical surface of the extension and side wall are adapted to act as a bearing for the reception of a rotatable shaft.

The other casing member 16 is a disc of cylindrical form and is adapted to close off the open end of the main casing member. Centrally thereof the disc is provided with an integral tubular cylindrical extension 17 having an outer wall 18. Similarly, the smooth inner cylindrical surface of the extension and disc wall act as a bearing for the reception of a-rotatable shaft.

In the finished assembly the casing members 12 and 16 are brought together as indicated in Fig. l and for the purpose of securing them together are provided with suitably tapped sets of aligned holes, designated, respectively, 19 and 20, for the reception of a plurality of screws 21. For ease of mounting, the pump may be By way of illustration a right angled bracket 22 having an apertured attaching arm 23 adapted to telescope over the sleeve 14 is shown. It may be secured to the pump by a set of screws 25.

On its outer periphery the main casing member 12 is provided with an integral boss 26 having a single inner passage 27 extending between the pumping chamber 11 and a pair of divergently directed passages 28.

A rotatable driving shaft 29 of cylindrical form that is necked down at an intermediate point, as at 30, to form a smaller diameter portion bounded at each end by annular shoulder surfaces 31 serves as the main actuating element of the pump. The cylindrical surface of the small diameter portion is roughened, as by knurling, to establish a reliable frictional contact with the cylindrical surface of a plurality of planetary roller elements 32. The driving shaft 29 is journalled in the bearing sleeves 14 and 17 for rotation therein and may be driven by any suitable source of power (not shown).

A fluid containing tube 33 is disposed within the pumping chamber 11 and is formed into a single loop that entirely surrounds the driving shaft. The loop is of maximum size and lies in the outer perimetric regions of the pumping chamber for contact with the outer cylindrical wall. It will be noted that the tube lies. in a single plane in the pumping chamber since the end portions of the tube do not overlap to complete the loop but rather come together in abutting relationship. Thus, both ends pass through the common passageway 27 and then divide to pass through the individual passages 28.

The roller elements 32 are of cylindrical form and are of a length that is slightly less than the distance between the spaced shoulders 31. The rollers are disposed between the driving shaft and the tube 33 and as shown are preferably spaced apart equidistantly about the driving shaft. Thus, the rollers extend into the recessed portion of the driving shaft for frictional surface contact therewith and are progressed through an annular path by the rotation of the driving shaft.

As previously mentioned, the tubing is collapsible and depending upon the particular application of the pump may take a variety of forms. For example, in applications wherein extreme temperatures may be encountered or wherein the fluid to be pumped may be a strong alkali or acid, it is preferred to employ silicone tubing. On the other hand, in certain chemical applications wherein long Wear is quite important, it is preferred to employ neoprene tubing. As a further example, when blood is the fluid to be pumped, the tubing may take the form of a resilient ethylene compound.

The casing members may be formed of any suitablematerial and the various portions thereof need not be integral. However, they are preferably made of a moldjed highly polymerized synthetic resin, also commonly known under the trade name nylon. In this instance, it is preferred to employ cylindrical brass sleeve inserts 34 and 35 within the molded sleeve members 14 and 17, respectively. As the pump operates and the various parts thereof become heated to some extent, the nylon sleeves 14 and 17 expand until they finally grab the shaft 29 and preventfurther rotation. The use of the inserts 34 and 35 prevents this swelling action and permits relatively close tolerances to be maintained'beween the shaft and its sleeve bearings.

The cylindrical rollers may also be of nylon, in which case there is a tendency for them to expand and this offers certain advantages not found in any known prior art pumps of this nature. When the pump is operating, the rollers will expand and thus impose a high degree of compression upon the collapsible tube 33 which is desirable in an eflicient pump; however, when the pump is standing still, the rollers contract and the compression exerted thereby is materially reduced. Therefore, the

2,899,904 I a 7 p collapsible tubing is relieved of any severe continuous pressures and this greatly enhances the useful life of the tubing.

It may be seen that the casing is constructed in two parts in order to permit ready assembly and disassembly of the various pump elements. The operation of the pump should be self-evident in that as the driving shaft 29 is rotated the knurled surface 30 frictionally engages the roller elements to drive them in a planetary motion. As the rollers advance, they progressively compress the collapsible tubing to force the fluid contained therein forwardly in the direction of rotation and simultaneously to set up a suction effect rearwardly thereof. Thus, the only moving parts of the pump are the driving shaft itself and the roller elements.

During operation the shaft 29 is prevented from shifting longitudinally relative to the casing 10 because the roller elements interact between the shoulders 31 on the shaft and theside walls of the casing.

The arrangement of the tubing in a single plane is an important feature of the present invention in that the resistance offered by the tube to the pumping elements is made substantially constant. It has been found that an overlap creates an excessive power demand that sometimes requires an oversized driving motor for the pump. In addition, the overlap arrangement tends to create more severe pressure concentration of the collapsible tubing. For best operating efiiciency, however, the common passage 27 must be small enough to prevent the introduction of slack in the system as this'would tend to disengage the roller elements from the driving shaft.

It should be understood that the description of the preferred form of the invention is for the purpose of .ing sleeves, a drivingshaftpassing through said chamber and rotatably supported on said sleeves, one of said tubular extensions having an open outer end to accommodate said driving shaft and the other extension having a closed outer end'to substantially'isolate the pumping chamber, a length of collapsible tubing formed into a single loop surrounding said shaft in vsaid'casing and arranged in a common plane that is substantially normal to the axis of said shaft, the end portionsof said tubing loop being coplanar and in side-b-y-side contact within said chamber and being turned radially outwardly to extend through a common opening in said circumferential wall of said casing, and planetary roller means disposed between said shaft and said tubing and in frictional surface contact therewith, said roller means being of such radial dimension as to compress said tubing against said circumferential wall of said casing in the region of contact such that rotation of said shaft drives said roller means along an annular path to momentarily compress successive portions of said tubing.

2. A pump of the class described comprising a casing defining a cylindrical pumping chamber bounded about its outer extremity by a circumferential wall, said casing being formed with tubular extensions at opposite sides of said chamber, metallic bearing sleeves snugly mounted in said extensions, a driving shaft passing through said 4 chamber and rotatably supported in said sleeves, a length of collapsible tubing formed into a single loop surrounding said shaft in said casing and arranged in a common plane that is substantially normal to the axis of said shaft, the end portions of said tubing loop being coplanar and in side-by-side contact within said chamber and being turned radially outwardly to extend through a common opening in said circumferential wall of said casing, and planetary roller means disposed between said shaft and said tubing and in frictional surface contact therewith, said roller means being ofsuch radial dimension as to compress said tubing against said circumferential wallin the region of contact such that rotation of said shaft drives said roller means along an annular path to momentarily compress successive portions of said tubing.

3. A pump of the class described comprising a casing having a cylindrical pumping chamber bounded about its outer extremity by a circumferential wall, a driving shaft rotatably supported in said chamber, a length of collapsible tubing formed into a single loop surrounding said shaft in said casing and arranged in a common plane that is substantially normal to the axis of said thatrotation of .saidtshaft drives said roller means along an annular path to momentarily compress successive portions. of said tubing.

4. A pump of the class described comprising a casing having a cylindrical pumping chamber bounded about its outer extremity by a circumfential wall, a driving shaft rotatably supported in .said chamber, a length of collapsible tubing formed into a single loop surrounding said shaft in said.casingandarranged in a common plane that is substantially normal to the axis of said shaft, the end portions ofsaid tubing'loop being coplanar and in side-by-side contact within said chamber and being turned radially outwardlytouextend through a common opening'in said'circum-ferential Wall ofsaid casing, and roller means disposed between said shaft andsaid tubing and rotatable with respect to said shaft, said roller means being of such radial dimension as to compress said tubing againstsaidcircumferential wall of said casing in the region of contactsuch that rotation of said shaft drives saidroller means along an annular path to momentarily compresssuccessive portions of said tubing.

;;=References Cited in the file of this patent UNITED STATES PATENTS 

